1. Field of the Invention
This invention relates in general to wireless communications systems, and more specifically, to a Subscriber Identity Module (SIM) enabling Advanced Voice Services (AVS) including Push-to-Talk (P2T), Push-to-Conference (P2C) and Push-to-Message (P2M) on wireless handsets and networks.
2. Description of Related Art
Group-based voice services, such as two-way half-duplex voice calls within a group or between individuals, also known as “Push-to-Talk,” “Press-to-Talk,” PTT or P2T, have enormous revenue earnings potential for wireless networks, such as cellular networks and personal communications systems (PCS) networks.
Moreover, the Assignee has introduced Advanced Voice Services (AVS) including improved implementations for P2T, as well as novel group-based voice services such as Push-to-Conference (P2C), Upgrade to Conference (upgrade from P2T to P2C), Push-to-Message (P2M) and group SMS (Short Message Service), for wireless handsets and networks. More information on these advanced voice services can be found in the cross-referenced applications identified above.
To support these advanced voice services, improved handsets are required. Of special interest are handsets that use SIMs (Subscriber Identity Modules). SIMs are embedded with circuitry and when inserted into a handset provides wireless phone service on a particular network. In this context, SIM is generically used to represent SIM (GSM), R-UIM (CDMA) and ISIM.USIM (3G networks).
SIMs store most of the logic required of a handset for providing cellular service, as well as many other functions, including call logs, voice mail, SMS (Short Message Service) and GPRS (General Packet Radio Services) for Internet access. In addition, SIMs store contact information and other user information, making such information portable among handsets.
Consequently, there is a need in the art for handsets that support advanced voice services for wireless communications systems, and more specifically, to SIMs that support advanced voice services, such as Push-to-Talk (P2T), Push-to-Conference (P2C), Upgrade to Conference (upgrade from P2T to P2C), Push-to-Message (P2M) and group SMS (Short Message Service). The present invention aims to satisfy this need.